Bubbles/Craters in Cement Based Leveling Compound/SBR mix

[RzB]

Ok - I'm doing something wrong but what? This is really frustrating and beginning to tick me off.

I recently damp proofed an "old" section of the garage that worked out really well - see....

However the floor was a bit of a problem. All worked out well in the end but only after some backbreaking hours.

I used a Cement Based Leveling Compound/SBR mixture. Evidently the SBR makes the mixture waterproof, more workable, flexible and stronger. The problem I had was bubbles in the mixture when laid. These popped and left craters in the finished surface. I'm not talking about the odd one here and there... It was literally covered! see...

This was put down to over entheusiastic mixing with one of these...

I spent hours down on my knees filling each hole by hand.

So when I came to next section I decided to mix by hand. Small shovel in a builders tug...

Guess what - exacly the same - bubbles and craters. More hours kneeling/filling... Hmmm...

More discussion with the vendor of the stuff..

Ok - do the mixing then let it settle in the tug for a while... also buy a spiked roller from a builders merchant and use that--- then you'll be ok...

Well none of the builders merchants had a clue about a spiked roller... But I managed to buy one from here...

See picture here...

I have just done one further bag on the next section... mixture left to settle, then pour, spread with trowel. As bubbles start to appear splat them with the roller... Great - but hang on.. they re-appear... In fact the roller seem to have just about zero effect...

Is there an expert out there that can tell me what I'm doing wrong!!!!!! Please!!!

Roy

[The3rd Earl Of Derby]

You're pulling our leg? thats a good shot of the moons surface. ;-)

-- Sir Benjamin Middlethwaite

[GzB]

Yes - I thought that myself....:-) but...

Honest it's the floor... not only that but it's not the worst part either.... Some parts are more craters than non-craters !!!

Help!! Roy

[The3rd Earl Of Derby]

Have you thought for one moment it might be the product is a load of erm! dog muck? considering they ask you to buy a needle roller if this occurs.

I've laid a floor in similair stuff and havn't had experienced craters or bubbles in the mix.

-- Sir Benjamin Middlethwaite

[sponix]

You paid HOW MUCH????!!!!

I use a bit of old bent coathanger in a cordless drill.

sponix

[The3rd Earl Of Derby]

Oh! do be realistic.

I paid £2.99 for my mixing paddle from the local diy shop not shed, I thought he was going to ask a silly price like £8 or more.

-- Sir Benjamin Middlethwaite

[John Armstrong]

Try damping the floor well before laying the levelling compound. When I put some down on a rather porous concrete floor, if the concrete wasn't damp almost to the point of standing water, the water from the mix soaked into the concrete, to be replaced by air bubbles from below.

[RzB]

John,

Yes, yes - floor was well damped prior to pouring compound...

Roy

[RzB]

Ok, ok - that was just the first picture I could find as an example of what I used......

Of course I would never spend that much on a tool that could so obviously be fashion from a coat hanger... :-)

The question is... why the bubbles and what am I doing wrong... ?

Roy

[The3rd Earl Of Derby]

I've given you my argument, what are you mixing it in? and did you degrease the floor before laying or it might be the fact the tempreture ie very cold floor?

-- Sir Benjamin Middlethwaite

[RzB]

Mixing in a builders trug... large plastic "bucket" like this , but yellow...

- No didn't degrease the floor. There was no grease on the floor to degrease.. So I and vendor of "stuff" decided that was not necessary.

Now interesting that you bring up temperature.... Yes it was quite cold today in the garage...about

6degC... However, the stuff I did earlier was at a much higher temp - probably about 15+deg C... so not sure that temp is a contributing factor...

Thanks for your thoughts... Roy

[RzB]

Hmm - but it's an interesting thought of how the bubbles might be forming...

Hmmm - mind buzzing on this one...

I didn't actually have "standing" water... but it was well soaked...

I wonder if it would be worth trying with a bit more damping... Hmmm...

Might give this a try...

Thanks, Roy

[keith_765]

Just a thought, try a second thinner coat spread with a steel float on a small test area. this might be the answer to filling in the holes.

[Mark]

Explain exactly how you are mixing this. From your Pic it looks like you are either whisking the mix _far_ too fast or dumping all the power into the water in one go, and then not Stirring _gently_ until _all_ the lumps have gone.

-

[david lang]

But this is no ordinary mixing paddle, this is a hand crafted, toledo steel, designer label mixing paddle. I bet Andy Hall has one.............

:-)

Dave

[zaax]

Cars drip water. Put a tray under the engine (if you see a liquid when you reverse out you have a problem).

I wouldn't have sealed it.

-- zaax

[Andy Hall]

Good heavens no. Mine's stainless.....

[Weatherlawyer]

You used too much Fairy Liquid.

Steer clear of fairies next time. (Personally I'd bury them good and deep.)

If you had allowed the air to vent by standing it for a shrt while you would have been better off. But I think if you had worked the floor as you laid it, concentrating on something like 18" wide strips perhaps?

How stiff was your mix?

[RzB]

Of course, of course.. :-)

Yes - did that... left it to stand for 10+mins

Yes - that's how it was done.. a 25kg bag mixed at a time. Then a strip poured and worked into place with a trowel.. then another pour and working with trowel.

Within 10secs of the mixture laying on the surface untouched, bubbles start popping up and forming craters. Further trowling - goes nice and flat then another 10secs and bubbles/craters.

Have tried all sorts from stiffish to runny. All pourable.

Roy

[RzB]

No - tried that. I found the only effective way to fill the holes is to use a wallpaper scraper type tool. Mix up a small amount of "stuff", and press it into the holes. Then wait for the holes to cave in and press it in some more... Tedious, very tedious.

Roy